Effects of zinc powder addition to Villa Gloss and Silka Lux marine enamel paints on corrosion resistance of mild steel

Abstract

The anti-corrosion properties of paints can be optimised when adequate proportion of the paint constituents are used. Effect of zinc powder addition to Villa Gloss and Silka Lux Marine Enamel paints on corrosion resistance of mild steel was studied. Quantitative Analysis and Potentiodynamic Polarisation Technique were used to evaluate the samples. The results indicate that zinc powder addition between 15 and 25 % significantly reduced the corrosion rate. The corrosion rate stabilized at approximately 0.10 mmpy when zinc powder added was above 15 %, independent of the exposure time. Potentiodynamic anodic polarization curves of the samples immersed in seawater showed that sample with 25% zinc powder addition exhibited highest corrosion potential and the least corrosion current density. Microstructural analysis of the samples also revealed the presence of pitting corrosion at the surfaces of the samples and their geometry, volume fraction and distribution vary with the zinc powder addition.Keywords: zinc powder, inhibition efficiency, potentiodynamic, weight loss, corrosion rate, pit corrosion NOMENCLATURE A1 uncoated sample. A2 sample coated with 10ml of white paint + 0% zinc powder. A3 sample coated with 10ml of red paint + 0% zinc powder. B1 sample coated with 10ml of white paint + 5% zinc powder. B2 sample coated with 10ml of red paint + 5% zinc powder. C1 sample coated with 10ml of white paint + 10% zinc powder. C2 sample coated with 10ml of red paint + 10% zinc powder. D1 sample coated with 10ml of white paint + 15% zinc powder. D2 sample coated with 10ml of red paint + 15% zinc powder. E1 sample coated with 10ml of white paint + 20% zinc powder. E2 sample coated with 10ml of red paint + 20% zinc powder. F1 sample coated with 10ml of white paint + 25% zinc powder.F2 sample coated with 10ml of red paint + 25% zinc powder. Cr corrosion rate (mmpy) Wt weight loss (milligrams) A Surface area of the sample (cm 2 ) T time of exposure of the samples in hour(s) metal density (g/cm 3 ) L length of the sample (cm) B breadth of the sample (cm) T thickness of the sample (cm)

Effects of Surface Preparation on the Corrosion Behavior of Mild Steel

“…The possible reason could be due to the fact that zinc spray caused the formation of an amorphous phase within the matrix of the corrosive medium, thereby enhancing the corrosion resistance property of the mild steel compared to samples with no zinc spray. However, the performance of the zinc spray diminished over time due to depreciation in the formed amorphous phase, which agrees with the report of Ayoola et al [20].…”

“…Beyond 14 days, the partial passivation experienced was due to saturation of dissolved oxygen since no spray was applied. This may also be due to the fact that corrosion products that often prevent further corrosion have been formed, which agrees with the report of Ayoola et al [20]. The aggressiveness of corrosion rate is a function of the type of substrate, oxygen presence [11], corrosion products formed [20], and inhibitor presence.…”

“…This may also be due to the fact that corrosion products that often prevent further corrosion have been formed, which agrees with the report of Ayoola et al [20]. The aggressiveness of corrosion rate is a function of the type of substrate, oxygen presence [11], corrosion products formed [20], and inhibitor presence. However, dissolved oxygen seems to be the most important, as earlier reported by Fauchais and Vardelle [11].…”

“…With all measurements taken, corrosion was clearly reduced with surface modification and spraying. The low corrosion rate was due to the passivation of zinc [20]. The adhesion of spray on a rougher surface reduced the corrosion rate.…”

Corrosive Influence of Varied Salt Solutions Concentration on Mild Steel

“…This is an indication that there were reactions between the specimens and the corrosive media. Corrosion rate increased with exposure time in the simulated corrosive media [17]. However, specimens in media F and H exhibited decrease in corrosion rate between 30 th and 42 nd days of immersion.…”